I have a Sharp Aquos LC42D72U (out of warranty) and I'm getting the dreaded Power/OPC blinking. A power reset does not always help.....fiddling with the HDMI connector and/or power and then performing a reset during power on sometimes helps, although, I'm just as likely to end up with sound and no video or full TV with no backlight.

Anyone have any ideas? Is there a firmware upgrade I can try?

This seemed to start happening after I plugged a new PS3 (HDMI) into the TV.